Simultaneous determination of tetracyclines in poultry muscle by capillary zone electrophoresis

A capillary zone electrophoresis method with UV detection was developed for the simultaneous detection and quantification of three tetracyclines in chicken meat samples: tetracycline (TC), oxytetracycline (OTC) and doxycycline (DOC). The separation conditions were: a running buffer containing 30 mM sodium phosphate, 2 mM EDTA disodium salt and 2.5% 2-propanol, pH 12.0, a 5 s hydrodynamic injection and a 14 kV separation voltage. Two different clean-up methodologies were employed: solid-phase extraction with C18 cartridges and ion exchange with Amberlite XAD7 resin. Analytes were detected at 360 nm in less than 12 min. LODs ranged from 61 ?g kg?1 for OTC to 68 ?g kg?1 for DOC with C18 cartridges, and 81 ?g kg?1 for DOC to 89 ?g kg?1 for TC with Amberlite XAD7 resin. The recoveries for TC, OTC and DOC obtained by both methods were between 85 and 95%, and the peak area repeatability for all of the samples was below 5% in all cases. Twenty-four samples of commercial chicken drumsticks were examined with both clean-up methodologies. In nine cases (37.5%) TC was detected, in a range from 197.8 to 2564.3 ?g kg?1, and in seven cases (29.2%) OTC was detected in a range from 83.0 to 2049.3 ?g kg?1. DOC was not detected in any of the tested samples. This method would be useful for the routine monitoring of TCs residues in poultry muscle.